av7110: check for negative array offset

commit cb26a24ee9706473f31d34cc259f4dcf45cd0644 upstream.

info->num comes from the user.  It's type int.  If the user passes
in a negative value that would cause memory corruption.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/media/dvb/ttpci/av7110_ca.c b/drivers/media/dvb/ttpci/av7110_ca.c
index 261135ded4815ecf909875773ddf19c9ceb50836..2dcd6c13cef722dba7f63ff574657e8d94c4ee37 100644 (file)
--- a/drivers/media/dvb/ttpci/av7110_ca.c
+++ b/drivers/media/dvb/ttpci/av7110_ca.c
@@ -277,7 +277,7 @@ static int dvb_ca_ioctl(struct inode *inode, struct file *file,
        {
                ca_slot_info_t *info=(ca_slot_info_t *)parg;
 
-               if (info->num > 1)
+               if (info->num < 0 || info->num > 1)
                        return -EINVAL;
                av7110->ci_slot[info->num].num = info->num;
                av7110->ci_slot[info->num].type = FW_CI_LL_SUPPORT(av7110->arm_app) ?